Electromagnetic devices



oct. 13,' 1959 P. E. UGN 2,998,783

ELECTROMAGNETIC DEYICES Filed Jan. 13, 1956 FIGI. F|G 2.

pierre l/gon By MM ELECTROMAGNETIC DEVICES Pierre Eugne Ugon, Sceaux,France Application January 13, 1956, Serial No. 559,053

Claims priority, application France January 25, 1954 1 Claim. (Cl.200-93) The present invention relates to electromagnetic actuatingdevices and is a continuation-in-part of my copending application SerialNo. 483,101.

The aforementioned application relates to electromagnetic actuatingdevices comprising an electromagnet associated with a movable armatureand arranged so that energization of the magnet winding by an electriccurrent produces movement of the armature due to magnetic attraction orrepulsion and movement of the armature performs some additionalelectrical or mechanical operation. For example, movement of thearmature may control the opening or closing of switch contacts in anelectrical circuit, in which case the device operates as an electricalrelay, or alternatively movement of the armature may control` somemechanical operation such as the locking or releasing of a member.

According to the aforementioned application, an electromagneticactuating device comprises essentially a core of magnetic materialhaving associated therewith an exciting coil or winding adapted to beenergized by an electric current -to form a substantially closedelectromagnetic circuit, and an armature of soft iron or the likemounted for rocking movement about an axis between two free and oppositepoles of said circuit and arranged to form a part of the magnetic pathof said circuit, in such a manner that, when said coil is energised, thesaid two opposite poles act on portions of said armature on oppositesides of said axis with forces being equal and opposite to each otherand at right angles to the faces of said poles, thereby producing acouple acting on the armature to turn it about said axis. By the staticas well as magnetic balance of the armature, which may be of extremelysmall weight, and proper biasing by a balance spring or the like, themoving parts are highly insensitive against outside accelerating forces,such as mechanical shock and vibration, thus preventing undesiredoperation of the relay or like device in practically any position duringuse.

It is an object of the present invention to provide improvements in suchelectromagnetic actuating devices.

It is a further object of the present invention to provide a form of theelectromagnetic actuating device which may operate as a polarised relay.

In order that the invention may be more fully understood, reference willnow be made to the accompanying drawing, in which:

Figure l shows diagrammatically, an electromagnetic device arrangedaccording to the aforementioned copending application,

Figure 2 reproduces the iixed magnetic circuit of Figure l with theaddition of a polarising member according to the present invention,

Figures 3, 4 and 5 show similar views of three modiications,

Figure 6 shows a detail applicable to the modification of Figure 4, and

Figure 7 shows an anti-bounce contact arrangement States arent finePatented Oct. 13, 1959 which possesses particular advantages for certainrelays controlling electrical circuits.

Referring to Figure 1, the electromagnetic device arranged according tothe aforementioned application comprises a central core 1 of magneticmaterial which is divided into two lateral branches 2. Between thecentral magnetic core 1 and the lateral branches 2 is located anelectrical energising winding 3. A thin platelike armature 4 of softiron, which can pivot about an axis 7, and which is associated with arestoring spring 7a, is arranged so that it is enclosed within the fixedmagnetic system provided by the elements 1, 2 and 3. Two very narrow airgaps separate respectively the two opposite ends of the armature 4 fromthe pole piece 1a formed on the free end of the core 1, and the oppositepole piece 5. The pole pieces 1a and 5 are so arranged as to present apair of laterally spaced parallel pole faces to the opposite endsurfaces of the soft iron armature 4. p

The entire magnetic circuit may be solid or laminated but preferablyiron laminations are employed.

Figure 2 shows a magnetic circuit for producing a polarised relayaccording to the present invention in which it is sufficient to replacethe counter pole 5 by a permanent magnet 5a in order to create in themagnetic circuit a permanent flux super-posed on the variable iiuxproduced by the excitation of the core 1 by the coil 3. In this way theoriginal magnetic circuit has only had to be modified slightly over theparticular arrangement of the aforementioned application so that theapparatus possesses all the inherent advantages of the polarised relay,amongst which may be mentioned notably the effects of detection peculiarto this class of relay, and the facility of being able permanently toposition their operating point in the region of their characteristic,which provides the greatest sensitivity.

Amongst the materials which may form the magnetic member 5a, ferritesare particularly recommended by reason of their high and strong coercivefield and consequently their resistance to demagnetization, so weakwhatever be the thickness in the direction of the magnetic field.

Figure 3 shows how the member 5a may be adapted to a fixed magneticcircuit arranged to receive a bent armature 4 as described in theaforementioned application.

In the modification of Figure 4 the permanent magnet has the form of afiat disc 8 and its arrangement under the excitation winding 3,necessitates a break between the central core 1 and its base, at leastin the arrangement which has been shown in Figure 4 and which has beenfurther shown in Figure 6. The ferrite disc in these two gures may be inthe form of a truncated pyramid or any other form offering the advantageof directing.1 the magnetic lines of force towards the core of the co1In Figure 6, in which the coil 3 is removed, there is shown one of themany means which may be employed to re-establish the continuity of thecentral magnetic circuit by intimately joining the ferrite disc 1 to thelaminations forming the central core 1 as well as to the lateralbranches 2 from which they have been separated.

Furthermore, Figure 4 shows the elements, 1, 2, 3 and 8 separated byspaces, whilst once the arrangement is complete, no space exists betweenthe elements and the continuity of the entire magnetic circuit must beassured after a cut has been made in the course of manufacture at thebase of the central core 1.

Other known devices applicable to magnetic circuits may also be employedwith advantage for such connections in order to give to them the highestpermeability.

t p A U 2,908,783

In some embodiments of the invention, use may also be made ofanti-bounce devices of the type indicated in Figur-e 7. This figureshows two relay contacts, comprising on the one hand a movable contact10 mounted on the armature 4 turning about its` axis 7, and on the otherhand the contact 1li Vmounted on its flexible blade 19, of which thebent end 19a rests slightly on a rigid part 20 in the state of rest.When the movement of the armature causes the contacts 10 and 11 toengalge, the blade 19 is ilexed and the rubbing of its end 19a on thesurface 20a of the rigid part 20 quickly dissipates the energy of theshock so that it does not produce any rebound or vibrations. After theshock the contact carrying blade 19 returns aperiodically to its restposition, but the rubbing, which acts as a brake, tends towards zero, asthe blade approaches its rst position such that it cannot be displacedor modied in the course of repeated operations of the relay.

I claim:

An electromagnetic device, comprising a core of magnetic material havingthree limbs, the central and at least one outer limb providing asubstantially closed magnetic circuit having two opposite poles spacedfrom each other, an electric excitation winding associated With saidcore, a mechanically balanced armature mounted for rocking movementabout an axis within the magnetic field produced between said two polesand having its opposite ends opposed, each by one of the pole faceswhich are arranged to exert equal magnetic forces on opposite sides ofsaid armature thereby producing a couple acting on the armature torotate it about said axis, an electrical contact assembly comprising arst contact member and a second contact member, means for mounting therst contact member as an arm extending from the armature so that it canmove into and out of engagement with said second contact member uponmovement of said armature, said second contact member comprising a rigidsupport and a ilexible blade mounted on and parallel to the rigidsupport and carrying a contact which is engaged by theriirst` contactmember and a bent end portion to said flexible blade which bears on therigid support, the arrangement being such that When the contact of saidsecond contact member is enlgaged by the iirst contact member, the bentend portion rubs along the rigid support thereby quickly dissipatingtheenergy of the `shock of engagement and absorbing any bounce orvibration.

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